Orthostatic stress via 60-degree head-up tilt decreased internal carotid artery blood flow by 9.4% (P<0.01) compared to supine, while vertebral artery blood flow remained unchanged.
Cross-Sectional (n=6)
Does orthostatic stress evoke regional differences in cerebral blood flow in the internal carotid and vertebral arteries in healthy young men?
Orthostatic stress evokes regional differences in cerebral blood flow and dynamic cerebral autoregulation between the internal carotid and vertebral arteries.
Effect estimate: -9.4 ± 1.7%
p-value: p=<0.01
It remains unclear whether orthostatic stress evokes regional differences in cerebral blood flow. The present study compared blood flow in the internal carotid (ICA) and vertebral arteries (VA) during orthostatic stress (60 deg head-up tilt; HUT) in six healthy young men. The ICA and VA blood flow were measured using Doppler ultrasonography. Dynamic cerebral autoregulation was also determined during supine (Supine) and HUT conditions, from the rate of regulation (RoR) in cerebrovascular conductance of the ICA and VA during acute hypotension induced by the release of bilateral thigh-cuffs. The HUT decreased ICA blood flow by -9.4 ± 1.7% (P 0.05]. These data indicate that orthostatic stress evokes regional differences in cerebral blood flow and possible differences in dynamic cerebral autoregulation between two main brain vascular areas in response to an acute change in blood pressure during orthostatic stress.
Sato et al. (Mon,) conducted a cross-sectional in Healthy (n=6). Orthostatic stress (60 deg head-up tilt) vs. Supine position was evaluated on Internal carotid artery (ICA) blood flow (-9.4 ± 1.7%, p=<0.01). Orthostatic stress via 60-degree head-up tilt decreased internal carotid artery blood flow by 9.4% (P<0.01) compared to supine, while vertebral artery blood flow remained unchanged.